In gas turbine engines, a portion of the total airflow from the compressor may be diverted to cool various turbine components. Specifically, a flow of bleed air may be extracted from a stage of the compressor to cool a stage of the turbine or other components. This diverted airflow, however, may consume a significant portion of the total airflow through the compressor. The management and control of these parasitic airflows thus may increase the overall efficiency and performance of the gas turbine engine.
The airflow extractions from the compressor may be controlled by one or more control valves positioned on the extraction lines. Although the actuators for these control valves generally may be mounted externally to the gas turbine enclosure so as to protect the actuators from the high temperatures within the enclosure, there are some control valves installed within the enclosure. The internal air surrounding these control valves may reach high temperatures and may be somewhat stagnant. In such situations, the heat reaching the control valves may not be dissipated such that the actuators may fail due to the high temperatures. As a result, known actuator cooling system may use complex mechanical or electronic devices so as to provide cooling. These cooling systems thus may be a parasitic drain on the overall gas turbine engine.
There is thus a desire for an improved control valve actuator cooling system. Preferably such an improved system may provide cooling to the control valve actuators without the use of complex components so as to provide increased reliability and decreased costs.